Non-rotating wire ropes



Jan. 29, 1957 H. SCHULLER 2,779,149

NON-ROTATING WIRE ROPES Filed Oct. '7, 1952 INVENTOR. 627/ J'cH ULLEAill Q94 NON-ROTATING WIRE ROPES Heri Schuller, Limbach, near Hamburg,Saar Territory, Germany, assignor, by mesne assignments, to George H.Rother, South Plainfield, N. J. 1

Application October 7, 1952, Serial No. 313,553

Claims. (Cl. 57148) (1) l+6+l1 or 1+6-}- 1?. strands (2) 1+3+9+15strands (3)-l+6+1l+17 or l+6+l2+18 strands wherein 1 represents thecentral core and the successive numbers represent the number of thewires or strands laid in successive layers in the order named in respectto said core. The latter may itself consist of a strand or solid wire ofany suitable material. Thus, according to Formula 1, six inner strandsare arranged be- 2,779,149 Fatentecl Jan. 29, 1957 Thecore of the ropemay consist of a strand or of a solid wire, depending on the type ordiameter of the rope, as will be further understood from the follow-(III) ing.

The bracketed numbers in the foregoing formulae indicate that thestrands may be replaced by a corresponding number of single wires forropes of relatively small diameter.

The invention will be further understood by the fol-, lowing detaileddescription, taken in conjunction with the accompanying drawing, formingpart of this specification and wherein:

Figures 1, 2 and 3 are diagrammatic cross-sections through preferredwire rope constructions according to tween a core and eleven outerstrands, while according to Formula 2, two inner layers of three andnine strands, respectively, are arranged between the core and a layer offifteen outer strands.

In such a construction, all the strands have substantially the samediameter and wire structure. The core may consist of a rope of hemp orother suitable material. Each strand is laid separately, in such amanner that the inner layer or layers between the core and the outer ortop layer, forming so to speak an inner rope, are laid in a directionopposite to the outer layer, in order to secure the desired freedom fromtwist or rotation of the rope, such as when used to lift an unguidedload.

A disadvantage of the known constructions is due to the crossing orintersection of the wires of the individual layers, on the one hand, andto the presence of relatively large open spaces between the layers, onthe other hand, resulting in a limited engagement or contact surfacebetween the layers. Thus, the constructions can at best be designated asreducing rather than eliminating the tendency of the rope to rotate andto unwind under load.

Among the objects of the present invention are to provide an improvedand novel construction of the inner layers or inner rope of amulti-layer wire rope, while using approximately the same number ofouter layers as in conventional rope designs; to more fully utilize agiven cross-section or to improve the packing factor of the rope; toincrease the breaking strength of the rope; to strengthen the structureof the inner strands; to increase the number of inner strands in theinterest of improving the freedom from rotation under load; to enablethe use of strands or wires of adjacent layers hav ing an equaldiameter; to enable the use of strands for the entire rope made ofsubstantially the same type of wire of equal diameter; to substantiallyeliminate crossing or intersection of the wires of the inner strands orlayers; and to provide an improved core structure suitable for ropesaccording to the invention as well as designs known in the prior art.

-'The above objects of the invention are obtained esthe above formulae1, II and 111, respectively;

Fig. 3A is a perspective view of a piece of rope with one end cut toshow the core, the inner strands and the outer layer arranged inaccordance with the invention; and

Figure 4 illustrates a preferred core construction for multi-layer wireropes according to the invention.

In all the figures of the drawing, the strands are represented bycircles for simplicity of illustration, the wires being indicated foronly some of the strands (Figure 2). In this representation, the circlesdenoting the wires or strands in a layer do not touch, since thesections are. actually ellipses rather than circles, as shown in thedrawing. r

i In all the figures, the core is designated by the letter a, and theconsecutive strands or layers, starting from the inside, are designatedas b, c, d and e, respectively. The drawing clearly shows theinterengagement of the inner strands or layers which are laid inparallel or withequal pitch or length of the lay, while the outerstrand(d according to Figures 1 and 3, 2 according to Figure 2) is wound ontop of or in cross lay arrangement with respect to the inner strands. Aspointed out, the innermost strand b next to the core a may consist of alayer of solid wires, such as shown in, Figure 2.

' diameter. The laying of the inner strands b and 0 will 7 wires (b)plus a 7-wire central strand or core (a).

be further explained hereafter." 7 7 Referring to Figure 2, this shows aconstruction of (9)+9+9+15=' 3 strands (c, d and e) plus 9 solid otherwords, 18 inner strands (c and d) are combined with 15 outer strands(e). The 24 strands of the layers d and e are of equal diameter and wireconstruction (7 wires each, in the example shown). The strands of thelayer 0 are necessarily of a lesser diameter, i. e. about one-half ofthe diameter of the strands d and e, and comprise each, in the exampleshown, 3 wires. For relatively small diameter ropes, such as from 6 to11 mm., the strands d and e may consist each of 3 wires of equaldiameter, while the layers a, b and may be constructed of acorresponding number of solid wires according to the designation (1)+(9) +(9) An alternative of the foregoing construction is the following:l+(8)+8+8-1-14 =30 strands plus 8 individual wires plus 1 core strand,for which the same considerations apply as are given hereinabove.

Referring to Figure 3, there is shown a construction of 7+ 7+ 7+ 18= 39Strands In other words, 7 strands of the layer b are combined with 14strands of the layer c1c2, resulting in 21 inner strands (b, 01, c2) and18 outer strands (d). The 7 strands of the layer 5 are of the samediameter and construction as the 7 strands c1, while the 7 strands 02are of a lesser diameter, about two-thirds of the diameter of thestrands 01 in the example shown. The core a in the example shown mayconsist of 19 wires. The core may also consist of 1+7 thin strands orsolid wires.

If, with the core strand consisting of 18 to 19 Wires, the constructionof the individual strands is suitably chosen, such as with the strandsb, 01 and d each comprising 7 wires and the strands 02 each comprising 3wires, it is found that, in such a case, all the wires of the rope, withthe exception of some of the wires of the core a, will be of about thesame diameter, thus making it possible to use wire of approximately thesame gauge throughout and to thereby considerably simplify themanufacturing operations and to reduce the cost of the rope.

With reference to the laying of the inner parallel strands b and '0,Figures 1 and 3, and c and d, Figure 2, i. e. the strands forming theinner rope between the core a and the outer or top layer d or e,respectively, it will be understood that with the wires of these strandsall being laid or arranged in the same sense or rotation, the wires ofadjoining strands will cross each other at their points of contact orintersection. In order to avoid these undesirable crossings, the senseof the lay or rotation of the wires of one inner strand such as c,Figure 2, is chosen to be opposite to the sense of the lay of the wiresof the adjacent inner strand, i. e. strand :1 in the example refeifredto.

Fig. 3A is a perspective view of a piece of rope with one end cut opento show the inner core a, the outer covering layer it and the twointermediate layers consisting 'of strands b and c. As shown the latterare layed with the same direction of rotation and having an equal pitch,whereby the strands c fit in the grooves between the stfarid b.Moreover, the wires 0' of the strands 0 have a twist which is oppositeto the twist of the Wires b of the" strands b, whereby the wires c' fitin the grooves between the wires b. This results in improvedcompactnessas well as non-rotatability ofthe rope together with the outer layer ofstrands d which are arranged in an opposite ray to the strands b and c.

This new rope construction or design according to the invention has thefollowing advantages: (a) an increase of the total breaking load of therope by about (b) the elimination of one of the operating steps in thelaying of the inner rope in the case of a three or multilayer ropestructure (Figures 2 and 3); (c) the absence of any wire crossingswithin the inner rope and-consequentstrengthening of the entire ropestructure; and (d) incre sed freedom from or resistance against rotationor twisting of the rope under load.

In non-rotating ropes constructed according to the prior art, the innerlayers are subjected to a greater stress, since for practical reasons itis not possible to increase the length of the lay of the outer strandbeyond a certainliniit advantages of the construction of the inven tionin this respect will be evident.

In the designs I and II, the layers at and e comprise 6 more strandsthan the adjacent inner layers c and d, respectively. As a result, thediameters of the strands of both layers may be substantially equal,although the invention is by no means limited to this construction.Evidently, the outer layers may have a different number of strands, suchas shown by the design Ill, Figure 3, without deviating from the scopeof the invention which is concerned essentially with the construction orarrangement of the layers inside the outer layer comprising the socalled inner rope.

The core of known multi-strand wire ropes may itself consist of a strandor a center rope made up of a plurality of wires and/or strands. Such arope then serves as a core about which are laid the main strands orlayers of the rope. According to a further feature of the invention,there is provided an improved core or center rope construction suitablefor multi-layer spiral ropes according to the invention as well as othertypes known in the art. M A disadvantage of all known core constructionsis the fact that the main strands of the rope are in substantiallypoint-to-point contact only with the core, whereby, with the ropepassing around a number of pulleys and being subjected to considerabletension, excessive pressures will occur at these points, resulting in asubstantial reduction of the life of the outer strands and in turn ofthe entire rope.

A wrapping of the strands with hemp, or the packing of hemp strings inthe outer grooves between the strands, has the disadvantage that themetallic cross-section of the coreis substantially reduced, while thehemp will become deteriorated and worn in time, thus leaving unde-'sirable open spaces and resulting in a loosening of the entire ropestructure.

The corefor a two-layer parallel-laid spiral rope, hav ing about eightor nine strands in each layer, may also consist of a central strandabout which are laid a number of individual wires, the latter serving torelieve the inter sections between the main strands and the strands ofthe core. Such an arrangement, however, is limited to ropes ofrelatively small diameter, since for the larger diameters the individualwires will become too heavy.

According to the present invention, there is provided an improved coreconstruction, especially for multi-strand ropes, which substantiallyavoids the above defects; which makes it possible to substantiallyreduce the manufacturing time and labor; and which will result inincreased metal cross-section of the core as well as in protection ofthe wires contacting one another within the rope.

These objects are obtained by a core construction corn-'- prisingessentially a layer of strands and a layer of an equal numberofindividual wires, both said strands and wires being laid around acentral wire in a parallel lay or winding arrangement. The outer wiresof the strands are chosen as thin as possible. As a result, they may beof a material having a relatively low strength, such as irori, and arepreferably coated with a layer of zinc; or equivalent material. In orderto further simplify the fabrication, the strands and individual wires ofthe core may be laid jointly with the main strands of the rope in asingle operating step by a parallel lay or winding oper= atio'n, i. c.with the pitch of the spirals of all the strands and individual wiresbeing substantially the same.

Referring to Figure 4, there is shown diagrammatically a core*strn'ctiire of this type according to the invention. Six individual orsolid wires m are laid ar'oi'lnd central wire I, about which there arelaid in turn and in the same sense six 1+9 wire strands n, in such amanner that the latter engage the grooves between adjacent wires m anddo not intersect or cross the latter, as clearly understood from thedrawing.

This center rope may serve as a core for the main rope comprised, in theexample shown, of- :1 number er strands shown in dashed lines in thedrawing. Alternativel'y, a multi-layer main rope maybe provided, inplace of the single layer, as will be readily understood. Such a coreconstruction has the, advantage over the known designs of asubstantially reduced manufacturing time as well as the absence of any.wire intersections or cross-over points within the core.

, Furthermore, by constructing, for instance, the strands rt'to consistof 1+9 wires h and g, respectively, whereby the latter'advantageouslyconsists of wire of iron coated with a layer of zinc, there is provideda kind of cushioning effect for the main strands. This, in turn, willavoid damage to the main strands of the core when the rope is subjectedto a considerable tension under load. This cushioning effect is improvedby the lubricating action of the zinc layer which also provides acertain protection against corrosion of the core and the outer wires ofthe rope proper.

The invention may go a step further by jointly laying the six strandsand the six individual wires of the core together with the six strandsof the rope in a single operating step. This is again carried out by aparallel lay method, in such a manner that each of the main strands 0engages two of the neighboring strands n, as clearly shown by thedrawing.

The advantages of this construction compared with previously knowndesigns are the following: (a) an increase of the metal cross-section ofthe core due to the fact that the strands of the core are located in thegrooves between the main strands and, accordingly, may have a greaterdiameter; (b) a better mutual support of the main strands and thestrands of the core and, in turn, a more favorable pressure distributionthroughout the rope, thus enabling a full utilization of the effect ofthe zinc layer; (0) an increase of the compactness and strengthening ofthe entire rope structure; and (d) elimination of a separate operatingstep in producing the core.

By alternating the sense of rotation of the wires, such as from a crosslay for the main strands (0) to a parallel lay for the strands of thecore (n), or vice versa, intersections or cross-over points between thetwo strands may be completely eliminated by a proper choice of thespiral pitch of the wires.

The foregoing will be further understood by reference to the followingpractical example:

Assuming a six-strand wire rope having a diameter of 19 mm. and madeaccording to known methods to contain a core consisting of six strandsof seven wires of 0.75 mm. each and a central strand of seven wires of0.8 mm. diameter, this Will result in a total metal cross-section (of 22mmfi Assuming further a strength of the wires of 160 kg. per mm. thetotal breaking strength of the wire will be 3,520 kg.

Referring now to the improved construction according to the invention,the core may comprise 6 strands (n) each consisting of 11 wires of 0.55mm. diameter and a central wire of 1.5 mm. diameter plus 6 individualwires =(m) of 1.05 mm. diameter plus one central wire (I) of 1.2 mm.diameter, resulting in a total metal cross-section of 32.6 mmf or a 48%increase compared with the previous construction. Assuming again astrength of 160 kg. per mm. for the single wires, totaling 16.9 mm. :and80 kg. per mm. (iron) for the outer wires of the strands of the core,totaling 15.7 mmF, the breaking load of the core will be 3,950 kg., thatis, an increase of 430 kg. over the previous construction despite theuse of iron wires. By the use of thin iron wires as a cushioning :means,it is furthermore possible to employ center and findividual wires of ahigher strength, such as for instance of 190 kg. per mmfi. In this case,the breaking load of :the rope will be further increased to 4,450 kg.

Regarding the manufacturing times, tests have shown 'that a thousandmeter core according to the old construc- :tion would require aboutfourteen hours, while the time :for laying the new core of an equallength is reduced to inner central wire.

about eight hours. Afurther advantage of the new core:

of the cross-section, while the increased diameter of the center andindividual wires of the core, laid with a 'rela-, tively small pitchwithin the main orouter rope, afford a substantialrelief for the mainstrandsof the rope under load. Furthermore, the use of iron wire for theouter wires of the strands of the core results in a relatively lowinternal or permanent stress obtained as a result "of the spiral lay ofthe strands of the rope.

If the diameter of the rope is reduced to such an extent that thestrands (n) of the core comprise only three wires, the strength of thelatter is chosen to comply with the special requirements and purposes towhich the rope is to be put. With still further decreasing ropediameter, the core is preferably manufactured with the six strands nreplaced by individual wires, whereby the core will now consist of twolayers of individual wires laid around an This construction isespecially advantageous for thin wire ropes, such as used on aircraftfor remote control or similar applications. In the latter case, all thewires of the core preferably consist of bare steel of high tensilestrength.

In the foregoing, the inventionhas been described with reference to afew illustrative devices. As will be evident, numerous variations andmodifications, as well as the substitution of equivalent elements andmaterials for those shown and described, may be made without departingfrom the broader scope and spirit of the invention, as defined by theappended claims. The specification and drawing are accordingly to beregarded in an illustrative rather than in a limiting sense.

I claim:

1. A multi-layer spiral rope comprising a core, a plurality ofintermediate layers each comprising a number of strands, the strands ofall intermediate layers being laid with the same direction of rotationand having an equal pitch and the direction of the twist of the wires ofthe strands of one intermediate layer being opposite to the direction ofthe twist of the wires of the strands of an adjacent intermediate layer,and a covering layer comprising a number of strands upon saidintermediate layers and having a relative sense of rotation opposite tosaid intermediate layers.

2. A wire rope as claimed in claim 1 comprising a first layer of sixintermediate strands, a second layer of six intermediate strands havinga diameter about twice the diameter of said first intermediate strands,and an outer layer comprising twelve elements each having a diameterequal to that of said second intermediate strands and enclosing saidintermediate strands and core.

3. A wire rope as claimed in claim 1 comprising a first layer of nineintermediate strands, a second layer of nine intermediate strands havinga diameter about twice the diameter of said first intermediate strands,and an outer layer comprising fifteen strands each having a diameterequal to that of said second intermediate strands and enclosing saidintermediate strands and core.

4. A wire rope as claimed in claim 1, comprising a first intermediatelayer of a given number of strands, a second intermediate layercomprising twice the number of said first intermediate strands, one halfof said second intermediate strands being of equal diameter to saidfirst layer of intermediate strands and the second half of said secondintermediate strands alternating with the strands of said first half andhaving a diameter about two thirds of the diameter of said firstintermediate strands, and an outer layer of strands enclosing saidintermediate strands and core and having a diameter also equal to thediameter of said first layer of intermediate strands.

5. A wire rope as claimed in claim 1 comprising a first intermediatelayer of seven strands, a second intermediate layer comprising a firstset of seven strands of a qim tn ql l bs: diamsitq 91 said fir t; ayerigtgr sipgngls, and an mite;- layer of e ightee n s tranlds hayipg adiglget filj al sqiequgl t9, the diamete; of; said first layer mqr iam sand References Cited in the file of this patent N ED STATE ATE T x 69 52- RWbfiP :-r-+--.-.---- M 1918 FOREIGN PATENIS,

